Binding post



J. B. BRADY Nov. 2 1926.

BINDING POST 2 Sheets-Sheet l Filed July 13, 1923 innt E i" I: all

Nbv; 2, 1926.

' J. B. BRADY BINDING POST Fil y 13. 1923 2 Sheets-Sheet 2 Patented Nov. 2, 1926.

UNITED STATES,

PATENT OFFICE.

JOHN B. BRADY, OF SOMERSET, MARYLAND, ASSIGNOR TO BRANDES LABORATORIES, INC., OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

BINDING ros'r.

My invention relates broadly to electrical circuit connectors, and more particularly to.

a protective' connecting device for electrical circuits. 5 One of the objects of my invention is to provide an attachment for binding posts on electrical apparatus whichit is desired shallbe protected against excessive electrical currents.

Another object of the invention is to provide an inexpensive construction of adapter which may be secured to various standard forms of binding posts, which adapter serves as a protective device against the passage of 15 excessive currents in the circuits connected with the binding posts.

Another object of the invention is to provide-an adapter for binding posts which carries a fuse through which the current must pass to reach the electrical circuit connected with the binding post, the fuse being of such value that it will be ruptured in the event that the energy being supplied to the electrical circuit connected with said binding post 8 should rise beyond a given limit.

A still further object of my invention is to rovide a device applicable to the filament lig ting binding post usually provided upon a radio" receiver to protect the electron tubes l used in the radio receiving circuits from excessive filament currents to which they might be subjected by mistake in choosing a filament potential. y invention will be more clearly under- N stood from the following specification by reference to'the accompanying drawings, in which:

Figure 1 shows the a plication of my invent on to any stander electron tube radio to receiving apparatus; Fig. 2. is a perspective View illustrating in outhne any type ofelectrbn tube radio receiving apparatus showing the rotective devices of my invention applied to the filament circuit binding posts .5 on the panel of the radio receiver; Flg. 3 is a cross sectional view through a binding post showin one form of fused ada ter screw't ed over the post; Fig. 4 1s a cross sectional vie w taken on line i -4 of in Fig. 3 showm one method of securing the auxiliary. bin ng post to the extremity of -:the fused adapter; Fig. 5 is a view partlally in cross section showing a modified construction of fused adapter; Fig. 6 is an enlarged fragmentary View showing a form of brush carried by the insulating bushing of the adapter shown in Fig.- 5 which is used for completing an electrical connection between the fusible conductor and the binding post upon which the adapter is secured; Figs. 7 60 and 8 show in cross section and in side elevation respectively another modified construction of adapter for a binding post; .Figs. 9, 10 and 11 illustrate a protective device for binding posts wherein the fusible member; is in the form of a removable element which may be renewed when ruptured by excess current; Fig. 12 isanother modified form of a renewablefused unit for binding posts; and Figs. .13 and 14 show another form which my inv ntion'may take.

With theliniireasing use of radio receiving apparatus by the general public in the reception of radio broadcast news, concerts, church services, music, and lectures, various types 'of electron tubes have become popular, many of which require different values of filament potential for lighting the cathodes. It is often confusing to those inexperienced in the art to determine the proper potential to be applied to the filament lightlng circuit for a given type of tube. A large numberof sets new employ electron tubes whose filament circuits are supplied from the ordinary dry cell, the filament electrodes having a rating of 0.25 or .060 ampere at axvoltage range of 1.1 to 5 volts and 3'volts respectively. It is not unusual for an inexperienced user ofradio apparatus to so misconnect the binding posts carried on the radio apparatus through hurry or mistake that the potential from the B battery or other undesired high potential might by chance find its way across the filament circ'uit and thereby instantaneously burn out expensive tubes. C

By my present invention I avoid the destruction ofelectron tubes by provlding an inexpensive construction of fused adapter which may be screwed over the ordinary bmding posts already provided on the set and then receive the usual cap screw which may have been previously re'movedfrom the standard binding posts on the set, the protectlng fuse wire being carried iii or by the adapter and 7 set andthe cap'screw on the adapter.

adapter of my invention is extremely inexy 10 while the terminals for the filament circuits.

interposed between the binding post on the The pensive and simple of manufacture, and may be produced on'a quantity production basis at reasonable cost. The fusible member on the adapter is also capable of renewal for the purpose of replacement after rupture on occasionof passage of excess current.

Referring more particularly to the drawings, the wiring diagram in Fig. 1 is illustrative of the application of my invention as a protection for the filament circuits of electron tubes in a radio receiver. ence character 1 indicates a standard form of regenerative electron tube receiver connected with an antenna system. The electron tube 2 is connected to rectify the incoming signal energy and electron tubes 4 and 5 function as audio frequency amplifiers for the rectified energy. The filamentcircuit for electron tube 2 is'represented at 6. The filament circuit for the tubes 4 and 5 has been shown at 7. The terminals for the filament circuit of'tube 2 are re resented at lament circuit 7 are shown at 11.. For the purpose of illustrating the application of my invention I have shown separate batteries A and A I provide fusible-members 8 and 9 in the filament circuits in such position that energy cannotpass from any external source to the' filamefit circuits without traversin the fusible links 8 and 9. These fusible members are constructed so that they. are readily adapted to any form of standard binding post already employed on a cabinet containing the radio apparatus in such osition that, the" ordinary binding post lea mg to the filament circuits interior of the cabinet are laced in circuit with the external source wit terposed between the external source and the filament circuits. In Fig. 2 I have shown a cabinet 3 which contains a two stage electron tubeam lifier with the tubes connected as re resente for the tubes 4 and 5 in-Fi-g. 1. I he input circuit terminates at binding posts 15 and 16. Binding'posts 17 and 12 are rovided for the B battery connection. Bin 'ng posts 11 are the terminals for the The cap screws are removed -from the bindingposts and small adapters carrying fusible members 9 screwed over the binding in place of the cap rv screws and then t 0 capscrews 12 and 14 are replaced uponan auxiliary binding post carried by the adapters. The addition of the adapters-slightly increases-the height of the post but not to such an extent that the bin (1 cover of the cabinet cannot be closed in t e usual manner. The additional height of the filament circuit bindin posts as compared to the height of the a jacent binding Refer the fusible member in- Thefusible members may be constructed in various forms. I have shown a number of these forms in Figs. 314. The usual binding post 11 is shownpositioned upon panel 18 with the shank 21 of the binding post extending through the panel 18 to rovide a permanent connection for the I lament lighting circuit interior of the cabinet 3 containing the radio apparatus. A pin 22 is usually provided on the binding post for centering and preventing rotation of the post. In Fig. 3 an annular insulating bushing 23 contains interior screw threads corresponding to the screw threads on the head of the binding post at 20. binding post 24 corresponding to the main binding post 11 is carried by the insulating bushing 23. This is accomplished in Fig. 3 by means of a short shank 25 dependin from the binding post 24 and secured wit respect to the insulating bushing 23 by means of a pin 26., A short metallic ring 29 is forced over the end of the insulating bushing 23 such that when the insulating bushing 23 is threaded over the head of the binding post 20, thering 29 makes electrical contact with the binding post 11. I connect the fusible member 9 between the ring 29 and the connection 27 in the binding post 24; The cap screw 14 which was removed from the head 20 may now be screwed over the head of the auxilia binding post 24 anchoring a wire '31 w ch connects with the external source of supply. It will be observedthat electrical energy can only reach the binding post 11-by passing through the fusible member 9. J

- The fusible member 9 may also be con- An auxiliary nected with the binding post -11 by means, i

of a brush member 32 in the form of a pin projecting from a lower edge of the insulating bushing 23 as shown in Figs. 5 and 6. The u'sible me nber 9 may be protected by means ofa sleeve 33 slipped over the outside of the adapter. 7

Connection ma also be made with the head of the binding post 20 by means of a metallic bushing 34 molded into the insulating bushing 23. The fusible member 9 may then be into osed between the metallic bushing 34 an the binding post 24 1X connection. at 37 and 36 respectively.

sleeve 35 may then he slipped over the outing connected between the caps 39 and 40 as indicated at 38. The renewable unit 38 is then clamped between the head 20 of In Fig. 12 the fusible member 9 is in the- ' form of a small spiral centered in a washer 43 which is clamped 'upon the head of the binding post 11 by screwing down the" insulating bushing 23., The other endof the fusible member 9 is clamped by means of themetallic sleeve 42 which carries the bindfuse member connecting with said first men tioned binding post and the other end connect ng with said last mentioned binding post.

2. An electrical connector, comprising 1n combination a binding post, an insulating member arranged to be inserted over said binding post, a second binding post carried by said insulatd member, a fuse member arranged to be clamped between said binding posts whereby electrical energy must pass through said fuse member in reaching ing post 24 and is forced over the insulated said first mentioned binding post.

7 been indicated supported in panel bushing 23. I F

a binding post has combination a bindmg post, an lnsulatlng tubular member arranged to be inserted In Figs. 13 and-14 44. v A removable member 46 having a metallic eyelet 47 in one end and a binding post 48 in the other end is arranged to be slipped over the head of the binding post 45. The fusii ble member .is interposed between the eye- I will be clear that it. maybe used for 'ments must be supplied let 47 and the binding post A connection 50 may then be made upon binding post 48 and the energy passed to the main binding post 45 by way offusible member 9.

While I have illustrated this fusible connector in connection with electron tulies (it ing posts anyw re .in the electrical 1 art 1 whereiit is desire to protect delicate instruments. The size of the fuse .is,selectedto provide the proper. factor of safety for the tubes, suflicient variation being allowed to take care of such variations as'might be imposed upon the circuit. It is also clearly understood that various sizes of fusible e1e-- to protect difi'e'rent values of load. I

While I have described my invention in. certain limitedaembodiments and illustrated only 'a few of e many forms which it may take it is to be understood that modifications claims.

te'rs Patent of theiUnited said-first mentionedpost, oneend of said in details may be madeand that I intend no I limitations upon the invention other than are imposed by the scope of the appended Let fol- What I claiin and desire to secure by States is as lows-z 9 I v I I 11; An electrical connector comprising 111 combination a screw 'threadedbinding post,

3. An electrical connector comprising in over said binding post,'said member having a length substantially greater than the height of said binding post, a second binding post carried in one end of said member forming an end closure for said member, a fuse member arranged to be clamped between said binding posts" whereby electrical energy must pass through said fuse member in reaching said first mentioned binding post.

4. An electrical cblmector comprising in combination a binding post, an insulating.

tubular member arranged to be inserted over said binding post, said member having a length substantially greater than the height of said binding post, a second binding post carried in one end of said member forming an end closure for said member, a fuse mem-' ber arranged to be clamped between said binding posts, said fuse member comprisin an insulated tube, a metallic cap on each end thereof, said .fuse being connected be tween said caps, one of said caps contacting With one of said binding postsand the other of said caps contacting'with the other of said binding posts whereby electrical energy must pass through said. fuse member m reaching said first mentioned binding post.

5..An electrical connector comprising in combination a screw threaded b' ding post,

an insulating screw threaded tu ular member having alength greater tha the height of said binding post, an auxiliary binding post carried in the upper end of said'tubular member, a fuse supported by .said' bushing,

agpair of members connecting said fuse to 7 both of said binding postsfsaid auxiliary binding post being so arranged in'said memher that i is at all times spaced from said-.

first--,ment1oned binding post".

JOHN B. BRAl)Y 

